Time-like pion electromagnetic form factors in kT factorization with the next-to-leading-order twist-3 contribution

Abstract We calculate the time-like pion electromagnetic form factor in the k T factorization formalism with the inclusion of the next-to-leading-order (NLO) corrections of the leading-twist and sub-leading-twist contributions. It's found that the total NLO correction can enhance (reduce) the magnitude (strong phase) of the leading order form factor by 20 % – 30 % ( 15 ° ) in the considered invariant mass squared q 2 > 5  GeV 2 , and the NLO twist-3 correction plays the key role to narrow the gap between the pQCD predictions and the measured values for the time-like pion electromagnetic form factor.

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